Well there is a difference between ```nohup``` and ```&```. It doesn't matter if you're committing from the command line as it can easily span a new process in the background - but if you're committing from a GUI it waits for the hangup signal which nohup suppresses.

```--quiet``` might work for Sismo itself - but the situation I experienced was PHP self printing a warning:

```
Warning: DateTime::createFromFormat(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function.
```